Crucial technologies of oil-transporting pipe leak detection and location based on wavelet and chaos

By detecting pressure and flux simultaneously, the leak of an oil-transporting pipe can be found and diagnosed synthetically. The flux of pipes is measured by an ultrasonic flow meter; considering the precision of the flux measured, a method based on the character of intermittent chaos of the Duffing system to detect weak signals under strong noise is introduced. The ultrasonic signals with a certain frequency could be extracted accurately from the complicated strong noise. So the flux of pipes can be computed precisely by an accurate ultrasonic signal. The location of a leak position is mainly determined by the time difference between the negative pressure waves measured by the pressure sensors located at both ends of the oil-transporting pipe. A singular point of a negative pressure wave can be judged accurately by a coefficient feature of the local extreme values of the wavelet transform. So, the precise location of the leak position of the oil-transporting pipe can be found. It can be shown by results of experiments that the precision of the leak location has been improved effectively, which can be about 1%.